Searching for a keyword or value is the basis of many computing applications, whether on an internet search engine or looking up a bank account balance.
This activity explores the main algorithms that are used as the basis for searching on computers, using different variations on the game of battleships.
Mordechai (Moti) Ben-Ari from the Weizmann Institute of Science, Israel has programmed linear, binary and hashing search in Scratch which can be downloaded in a zip file of the complete set of activities . Please read the ReadMe.txt for documentation.
Barbara Ryder at Rutgers University Computer Science Department has a binary search activity where students first think how they would search for a song on an MP3 player, and then they learn about binary search.
An older version of this activity can be downloaded in PDF format here. The content is similar to the current version, but there's some extra technical information.
The Mathmaniacs web side has a related activity (lesson 8)
MIT Open Courseware in Electrical Engineering and Computer Science has the following lecture Video: Lecture 9: Binary Search, Bubble and Selection Sorts by Eric Grimson and John Guttag.
Howstuffworks.com explains the large-scale application of these principles.